textproduct: Albany

WHAT HAS CHANGED

Latest 1630Z convective outlook has marginal risk brushing into Dutchess and Litchfield Counties, but higher risk for storms today looks to generally be to the south over the mid Atlantic into coastal New England

Have increased cloud cover for Thursday with frontal boundary stalled just to the south, but will keep POPs low with no precip.

With high pressure overhead and some clearing finally occurring, have blended the latest MOS guidance into the min temps for Thursday night into early Friday. With some lows in the low to mid 30s over the Adirondacks, have included some frost in the forecast for the higher terrain of the southern Adirondacks.

With guidance still showing some differences regarding precip start on Saturday, have lowered POPs slightly for northern areas on Saturday, as it may take some time for precip to impact far northern areas.

KEY MESSAGES

1) With a cold front settling southward, a few showers and thunderstorms are expected this afternoon into this evening across southern parts of the region. An isolated damaging wind gusts cannot be totally ruled out for locations within Dutchess and Litchfield Counties.

2) A return to more seasonable temperatures is expected Thursday into Friday. With high pressure overhead, some frost will be possible across the southern Adirondacks on Thursday night.

3) The next chance for widespread rainfall will be over the holiday weekend, although models continue to disagree on the exact timing, duration and amounts.

DISCUSSION

KEY MESSAGE 1...

A cold front continues to settle southward across the forecast area this afternoon. NYS Mesonet shows a noticeable drop in the dewpoints behind the front, with values down into the 40s and 50s already across the Adirondacks and Mohawk Valley. Plenty of clouds and some spotty showers are accompanying the front over the Capital Region, southern Vermont and Berkshires early this afternoon, which is keeping temperatures down as well. However, areas to the south over the mid Hudson Valley and NW CT continue to see hot and muggy weather ahead of the boundary, which is allowing for MLCAPE values in the 500-1000 J/kg range. 0-6 km bulk shear is solid over southern areas, with values in the 30-40 kt range. At the moment, the low level lapse rates are fairly steep as well, although the front is approaching quickly and the increasing cloud cover will be lowering these lapse rates soon.

Convection has already developed across parts of northern and central Pennsylvania and this activity is spreading eastward. However, the front is also dropping southward, so it will be a race between the developing convection and the approaching boundary. Based off the latest CAMs, most of the strongest activity will likely remain just south of the region for later this afternoon into this evening, although some convection could scrape far southern parts of the area (Dutchess and Litchfield County). This is shown in the latest 3km HRRR as well as probability fields from the 17z SPC WoFS output. Still, with the current mesoscale setup, enough instability and shear would suggest a damaging wind threat for our far southern areas, although this looks to exist only briefly, as the approaching front, will be lowering instability and dropping dewpoints as it settles southward. Will continue to message a brief threat for strong storms in our far southern areas, but the threat is a higher probability across PA, NJ and the NYC Metro area.

KEY MESSAGE 2...

Cooler air will be moving into the region for Thursday into Friday with the west to northwest flow. Temperatures will only be in the 60s for highs on Thursday, which is noticeably lower than the past few days. It will be very dry, as well, with dewpoints only in the 30s. The frontal boundary will be stalling south of the region on Thursday, so there still will be plenty of mid and high level clouds, especially from the Capital Region on southward.

Some clearing will finally occur on Thursday night with surface high pressure just north of the area. With clearing skies and light to calm winds, have gone lower than NBM temps and blended the latest MOS guidance into the forecast. This allows for min temps in the middle 30s over the high terrain of the Adirondacks and southern VT, with even some upper 30s across the Mohawk Valley, Catskills, Glens Falls area, Taconics and Berkshires. Some frost will be possible across northern areas and a Frost Advisory may be needed for a few zones.

Temps will quickly warm up on Friday with a comfortable day with plenty of sun. Highs will be in the 60s to low 70s across the region with dewpoints still in the 30s. Some clouds may increase late as the front starts heading back northward as a warm front.

KEY MESSAGE 3...

Some rainfall is expected across the region on Saturday, although guidance differs on how quickly it moves northward and exactly how far north the rainfall can get. Have stayed close to the NBM for Saturday for POPs, but did lower POPs across far northern areas based off the latest 12z guidance. This should be a steady light to moderate stratiform rainfall and no thunder is expected at this time.

There are some differences in the guidance as well when the rainfall tapers off, but there should be a period of drier weather at some point for Sunday. Still, it's unclear if appreciable clearing occurs. With the expected clouds and precip, temps will likely be held down into the 60s on both Saturday and Sunday.

More showers are expected with the passing upper level disturbance as well. This looks to be Sunday night, but could linger into part of Monday as well. Some clearing should occur during the day on Memorial Day with temps a little milder than the weekend, but it still probably won't be ideal Memorial Day weather. With some differences still in the models, this continues to be low confidence and some changes are still possible.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Through 18Z Thursday... VFR conditions are expected to dominate across all terminals throughout this TAF period, characterized by varying mid-to-high cigs. The lone exception will be at KPOU, where a PROB30 group highlights the slight possibility of isolated thunderstorms this evening, with the potential for MVFR vis with associated heavier downpours. All terminals are expected to see cigs transition to higher levels (above 10k ft) overnight, persisting into Thursday morning.

Westerly to northwesterly winds will remain gusty through the remainder of the afternoon and into the evening, with gusts ranging from around 15-25 kts. The strongest gusts are expected at KALB and KPSF. These gusts will begin to subside around sunset tonight, with winds beginning to veer more northerly at all terminals around that time. These winds will persist through the end of the TAF period, with a chance for gusty winds returning at KPOU around sunrise.

Outlook...

Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: High Operational Impact. Likely SHRA. Saturday Night: High Operational Impact. Likely SHRA. Sunday: Moderate Operational Impact. Likely SHRA. Sunday Night: Moderate Operational Impact. Chance of SHRA. Memorial Day: Moderate Operational Impact. Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.